The pan-European Stoxx 600 closed slightly lower, down by 0.17 percent with business sectors and major bourses revealing a mixed bag at the end of the day's trading.

Europe's basic resources recovered from losses earlier in the day, rallying 1.7 percent by the market close. Luxembourg-based steel-maker Arcelormittal topped the sector, closing up over 4 percent. The sectorhad previously been weighed down by concerns of a global trade war. President Donald Trump is widely expected to unveil up to $60 billion in import duties on Chinese goods by the end of the trading week. Investors are anxious the looming charges could escalate into a full-blown trade war, threatening global economic growth.

Oil and gas also performed well, rallying during afternoon trade to close up 1.24 percent. The U.K.'s Tullow Oil was the best performing company, closing up nearly 4 percent.

Utilities oscillated between positive and negative trade, ultimately closing up 0.4 percent. Italy's A2A and Germany's E.ON both had their target stock prices upwardly revised by Kepler Chevreux on Wednesday morning. Both closed in the green, with A2A up over 1 percent.

In individual stocks, Ubisoft surged to near the top of the European benchmark after Vivendi chairman Vincent Bollore lost a two-year battle against its founders. French media group Vivendi announced plans to sell its stake in the video games-maker for 2 billion euros ($2.45 billion) on Wednesday. Shares of Ubisoft ended the trading day up 3.8 percent.

Europe's second-largest home improvement retailer slumped to the bottom of the index as the group forecast a mixed outlook. Kingfisher posted a better-than-expected rise in annual profits on Wednesday but said a more "uncertain" future was a concern. Its shares had tanked 10.7 percent by the market close.

Federal Reserve in focus

U.S. stocks were trading higher Wednesday as investors looked ahead to the Federal Reserve's latest decision on monetary policy as well as Jerome Powell's first post-decision news conference as chair.

Investors appear relatively convinced that the U.S. central bank will raise interest rates to 1.75 percent, up from 1.5 percent. The Fed is widely anticipated to signal three or four further rate hikes for the year as a whole.